Ключевые слова: abstract, advertisement, advertising, backdrop, background, billboard, blackboard, blank, board, chalk, chalkboard, class, classroom, closeup, college, crayon, design, dirty, draw, education, effect, element, elementary, empty, equipment, erase, exam, green, grunge, highschool, learn, learning, leisure, lesson, nobody, object, old, pattern, rubbed, school, space, student, study, surface, teacher, texture, view, vignette, wall, wallpaper, white,